Challenging Solutions to High Capacity Rock Anchors

摘要

High Rock Dam, a 75-year old concrete gravity structure approximately 935 ft long,required remediation of the spillway in order to meet the factor of safety criteria for theproject design loadings. High Rock Dam is located in North Carolina on the Yadkin River,and is owned and operated by the Yadkin Division of Alcoa Power Generating Inc. Theremediation plan included the installation of 19 multi-strand, epoxy coated and filled, highcapacity post-tensioned anchors with capacities up to 1850 kips. The anchors wereinclined 28 degrees from vertical and oriented in an upstream direction. In general, anchorcapacities were maximized by locking-off at 70% of the ultimate strength, therebymaximizing the reserve capacity in the event of future changes in the design loadings.This paper discusses the development and execution of the rock anchor program at HighRock Dam, the field problems encountered and the resolution of each problem by theProject Team that consisted of the Owner, Engineer, Contractor, and the Federal EnergyRegulatory Commission (FERC).